CODEWITHSUNDEEP
python
Max_il
Max_il

Reputation: 151

python compare elements in alist of tuples with the same index

I have a list of tuples :

list = [(u'RHSA-2017:1270', u'Red Hat Enterprise Linux 6'), (u'RHSA-2017:1271', u'Red Hat Enterprise Linux 6'), (u'RHSA-2017:1270', u'Red Hat Enterprise Linux 7')]

i need to compare index1 element for each tuple i.e 

'Red Hat Enterprise Linux 6'

which is the same for the first 2 tuples

and the first index element in tuple 3 ,which is :

'Red Hat Enterprise Linux 7'

my goal is once i detected that element index 1 in tuple 2 is duplicate

remove this tuple from the list.

i have tried to create anew list with the required tuples by i am getting

an empty list

new_list = []
for i in list:
    rhel_ver = str(i[1])
    if rhel_ver not in i:
         new_list.append(i)

getting empty list. how can i get only the first tuple that contains the rhel version ,i.e:

list = [(u'RHSA-2017:1270', u'Red Hat Enterprise Linux 6'), (u'RHSA-2017:1270', u'Red Hat Enterprise Linux 7')]

Upvotes: 1

Views: 92

Answers (3)

Adewole Adesola
Adewole Adesola

Reputation: 199

You can use python OrderedDict to create a new list setting the index 1 (second element in the tuple) as key. This will remove any duplicate. You can then produce a new list from the Ordered Dict. python 2.7

import collections
tagPairs=collections.OrderedDict()

lst = [(u'RHSA-2017:1270', u'Red Hat Enterprise Linux 6'), 
       (u'RHSA-2017:1271', u'Red Hat Enterprise Linux 6'), 
       (u'RHSA-2017:1270', u'Red Hat Enterprise Linux 7')]
for i,v in lst:
    tagPairs[v]=i
unique_list=[]
for k,j in tagPairs.items():
    unique_list.append((j,k))
print unique_list

Upvotes: 0

Pedro von Hertwig Batista
Pedro von Hertwig Batista

Reputation: 3012

You can use the any built-in to make a new unique list:

my_list = [(u'RHSA-2017:1270', u'Red Hat Enterprise Linux 6'), (u'RHSA-2017:1271', u'Red Hat Enterprise Linux 6'),
           (u'RHSA-2017:1270', u'Red Hat Enterprise Linux 7')]

unique_list = []
for element in my_list:
    if not any(tup[1] == element[1] for tup in unique_list):
        unique_list.append(element)

print(unique_list)

Upvotes: 2

tobias_k
tobias_k

Reputation: 82929

You can keep track of the elements you've already seen in a set:

lst = [(u'RHSA-2017:1270', u'Red Hat Enterprise Linux 6'), 
       (u'RHSA-2017:1271', u'Red Hat Enterprise Linux 6'), 
       (u'RHSA-2017:1270', u'Red Hat Enterprise Linux 7')]
seen = set()
result = []
for rhsa, name in lst:
    if name not in seen:
        result.append((rhsa, name))
        seen.add(name)
print(result)
# [('RHSA-2017:1270', 'Red Hat Enterprise Linux 6'), ('RHSA-2017:1270', 'Red Hat Enterprise Linux 7')]

Upvotes: 2

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